Powershift & Automatic Testing and Service

Question 1

What are the 4 steps required in performing a torque converter stall test?

Answer 1

Lock the service and parking brakes
Select the highest possible speed range
Run engine at wide open throttle
Record engine RPM

Question 2

A pressure of 8 psia at the trans charging pump inlet is taken, this would tell you what about pump

Answer 2

Charging pump is cavitating

Question 3

What could cause a higher than specified stall speed(3)

Answer 3

Engine producing excessive power
slipping clutches in the TC
TC is cavitating

Question 4

Low clutch pressure readings at idle and normal at high idle would indicate what

Answer 4

There is significant leakage in the clutch application circuit

Question 5

Why is it important to bring trans to operating temperature before preforming operational tests

Answer 5

Shift system leakage increases as oil temp increases

Question 6

3 possible causes of low TC charge pressure are

Answer 6

Insufficient charge pump flow
Excessive leakage in clutch circuit
Excessive leakage in TC circuit